Improvement in keys for shaftings



@attriti-h att @anni affini,

Letters Patent No. 110,510, dated December 27, 1870.

yIMPROVMENTVIN KEYS FOR SHAFTlNGS.

The Schedule refer-.red to in these Letters Patent and making part of the same.

General Description 'with Reference to the Drawing..

Figure 1 is an end elevation of a shaft and key with pulley in position.

Figure 2 is, a perspective view of a key on an enlarged scale.

Figure 3 shows my preferred method of securing an arm to a rock-shaft.

A represents a shaft;

B, a pulley; and

C, the hub of the same, having a slot, c, for the key.

The key D is Iormed with a dat back, d, two vertical or nearly vertical sides, E E, and a concave gutter or channel, F, which extends along its frontsurface.

lhis concave is struck with a radius somewhat less than that ot' the shaft to which the pulley is to be secured, so as to form knifeedged bearings G G at the points where the terminations ot' said concave meet the ehamt'ered or inclined portions e e of the sides E E'.

'.lhe entering end el is slightly thinner than the other end.

This key is inserted in its seat in the customary way'and then driven home, which act brings its knifeedges G G to-bcar against the periphery ot' the shaft, very. slightly penetrating the latter, causing a very secure grip and attachment without lweakening or bowing the shaft, as is apt to be the case where a portion ot' one side is removed to torm the seat.

The chamfeled edges e e prevent the key having; the action ot'a turning tool to strip the shat't, to which they might be subject it' the sides E E' were carried up to meet the shaft without the described.ehamtered portions.

By using this key I dispense with the customary seat, which, besides rendering the shaft weaker, is liable to 'bend the same out ot' line in the act of driving the key.

While better than the ordinary key, for the reasons given, my device is far superior to a set-screw in the much more ell'eetive grasp -ot' the shaft, longer than the hub even, if necessary, and because it is not liable to cuta circumferential groove or'erease in the shaft, as the set-screw is.

Whenever it is desired to attach an arm, H, to a rock-shaft, J, I prefer the employment ot' t-no diametrically-opposite keys, la, as shown in lig. 3.

This device may also be employed as a shaft-coupler, or wherever it is desired to unite two rotating bodies.

, \Vhile prefering the form shown for ordinary purposes, partly because easily made of bar-steel, it is manifest that an elliptical, trapezoidal, circular, or other form may be given to the back and sides ot the key, providing that the concave bearing-surface with channeled-sided knife-edges be retained.

Claim.

I claim as new and of my invention- The improved key for shaftng, having theconcave face with chamfered-sided knife-edges, as explained.

In testimony of which invention l hereunto set my hand.

Y NATHAN STEDMAN. Witnesses:

Gmo. H. KNIGHT,

JAMEs H. LAYMAN. 

